In general, a cowl top panel of a vehicle is a panel which is disposed in a vehicle width direction corresponding to a lower portion of a front glass.
The cowl top panel is connected with a top end of a dash panel for separating an engine room from a vehicle room. When the vehicle collides, the cowl top panel is manufactured to represent stiffness together with the dash panel in order to prevent components mounted in the engine room from being pushed to the vehicle room.
The stiffness of the cowl top panel is sensitive various noises which are introduced into the vehicle room.
In this case, the noises introduced into the vehicle room include a load noise corresponding to a low frequency generated from a tire, and an acceleration permeation noise corresponding to a high frequency generated from an engine.
In this case, as the cowl top panel vibrates, the low frequency is transferred due to change in negative pressure of internal air in the vehicle room, and the high frequency passed through the cowl top panel and is transferred through the medium of air.
In order to prevent the noises from being introduced, a cowl top panel according to the related art blocks the load noise corresponding to the low frequency by suppressing vibration using a reinforcement plate for connecting a front surface of the cowl top panel with a rear surface thereof.
However, the acceleration permeation noise corresponding to the high frequency transferred with the air passes through the cowl top panel along the reinforcement plate to be introduced into the vehicle room.
Accordingly, there is a need for researches into a structure of a cowl top plate capable of simultaneously blocking a noise corresponding to the low frequency and a noise corresponding to the high frequency.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.